Opposition Leader Tony Abbott says he's not concerned who leads Labor to the next election.
The email circulation has been interpreted as an attempt by Labor caucus members loyal to Ms Gillard to warn Mr Rudd against any leadership destabilisation in an election year.
Before Mr Rudd's leadership tilt in February last year a video had appeared on YouTube showing him angry, red-faced and swearing with frustration.
Mr Abbott told reporters in Queanbeyan on Thursday he would be contesting the September 14 election, as "is the leader of the Australian Labor Party".
"In the end it is up to the Australian Labor Party to determine who their leader is and I think the public are inevitably dismayed at chaos and shambolic government in Canberra," he said.
"The trouble that we've got at the moment is no one is quite sure who is going to lead the Labor Party.
"The faceless men haven't decided who the prime minister will be."